Thin-film deposition apparatus using discharge electrode and solar cell fabrication method

Abstract

A discharge electrode, a thin-film deposition apparatus, and a solar cell fabrication method, which suppress the generation of a film thickness distribution and a film quality distribution, are provided. The discharge electrode includes two lateral structures 20 that are substantially parallel to each other and extend in an X direction; and a plurality of longitudinal structures 21 a that are provided between the two lateral structures, are substantially parallel to each other, and extend in a Y direction substantially orthogonal to the X direction. The longitudinal structures 21 a each include an electrode main body 35 whose one end 35 a is connected to one of the lateral structures 20 and whose the other end 35 b is connected to the other lateral structure 20 ; a gas pipe 41 disposed in a gas-pipe accommodating space 36 ; and a porous body 40 . An opening 38 opens to a substrate 8 and is covered with the porous body 40 . A gas diffusion path 37 connects the gas-pipe accommodating space 36 and the opening 38 . The electrode inner surface 39 faces the gas-pipe accommodating space 36 and opposes the pipe outer surface 42 b . A nozzle hole group 42 c is arranged in the second direction in the gas pipe 41 , and faces a section 39 a at a side opposite to the gas diffusion path 37 in the electrode inner surface 39.

1 . A discharge electrode comprising:
 two lateral structures that are substantially parallel to each other and extend in a first direction; and   a plurality of longitudinal structures that are provided between the two lateral structures, are substantially parallel to each other, and extend in a second direction substantially orthogonal to the first direction,   wherein the plurality of longitudinal structures each include
 an electrode main body whose first end is connected to one of the lateral structures and whose second end, which is the end opposite to the first end, is connected to the other lateral structure, 
 a gas pipe disposed in a gas-pipe accommodating space provided inside the electrode main body, and 
 a porous body, 
   wherein the electrode main body includes a first opening open at a counter electrode holding a substrate and a gas diffusion path provided between the gas-pipe accommodating space and the first opening to connect the gas-pipe accommodating space and the first opening,   wherein the first opening is covered by the porous body,   wherein the gas pipe has a nozzle hole group that penetrates from a pipe inner surface to a pipe outer surface of the gas pipe,   wherein the gas pipe, the gas-pipe accommodating space, the gas diffusion path, and the first opening extend in the second direction,   wherein the electrode main body has an electrode inner surface that faces the gas-pipe accommodating space and opposes the pipe outer surface, and   wherein the nozzle hole group is arranged in the second direction in the gas pipe.   
     
     
         2 . The discharge electrode according to  claim 1 ,
 wherein the nozzle hole group faces the electrode inner surface.   
     
     
         3 . The discharge electrode according to  claim 2 ,
 wherein the nozzle hole group is arranged in the second direction at a nozzle pitch L, and   wherein a gap distance w between the pipe outer surface and the electrode inner surface and an ejection area S of one nozzle hole of the nozzle hole group satisfy the following equation:
   0< S /(2 wL )<1. 
   
     
     
         4 . The discharge electrode according to  claim 2 , further comprising:
 a spacer disposed between the electrode inner surface and the pipe outer surface.   
     
     
         5 . The discharge electrode according to  claim 4 ,
 wherein the gas-pipe accommodating space has a first center axis,   wherein the gas pipe has a second center axis, and   wherein the spacer is provided on the pipe outer surface such that the spacer contacts the electrode inner surface before misalignment of the first center axis and the second center axis with respect to a direction orthogonal to the first center axis exceeds 25% of a gap distance w 1  between the pipe outer surface and the electrode inner surface when the first center axis and the second center axis are aligned.   
     
     
         6 . The discharge electrode according to  claim 4 ,
 wherein the gas-pipe accommodating space has a first center axis,   wherein the gas pipe has a second center axis, and   wherein the spacer is provided on the electrode inner surface such that the spacer contacts the pipe outer surface before misalignment of the first center axis and the second center axis with respect to a direction orthogonal to the first center axis exceeds 25% of a gap distance w 1  between the pipe outer surface and the electrode inner surface when the first center axis and the second center axis are aligned.   
     
     
         7 . The discharge electrode according to  claim 1 ,
 wherein a ratio S 2 /S 1  of a flow path sectional area S 1  of the gas pipe to a total ejection area S 2  of the nozzle hole group provided on each gas pipe is greater than 0 and smaller than ⅕.   
     
     
         8 . The discharge electrode according to  claim 1 ,
 wherein the material of the gas pipe and the electrode main body is an aluminum material.   
     
     
         9 . The discharge electrode according to  claim 1 , wherein
 the material of the electrode main body is an aluminum material, and   the material of the gas pipe is non-magnetic stainless steel.   
     
     
         10 . The discharge electrode according to  claim 1 , wherein
 said one of the lateral structures includes a header extending in the first direction,   the gas pipe includes a pipe end section protruding from the gas-pipe accommodating space at the first end,   the header includes a depression and a gas flow path communicating with the depression,   the header is attached to the first end in a removable manner such that the pipe end section is inserted into the depression, and   the gas pipe communicates with the gas flow path through the pipe end section and the depression.   
     
     
         11 . The discharge electrode according to  claim 10 , wherein
 the depression has a bottom surface and a sidewall having an annular groove,   an O-ring for sealing the gap between the depression and the pipe end section is disposed in the annular groove, and   a gap is provided between the bottom surface and the annular groove in the direction in which the pipe end section is inserted into the depression.   
     
     
         12 . The discharge electrode according to  claim 10 , wherein
 a key is provided on the pipe end section, and   a key groove that engages with the key is provided in the depression.   
     
     
         13 . The discharge electrode according to  claim 1 , wherein
 the electrode main body includes a first section and a second section that is attached to the first section in a removable manner such that the first section and the second section sandwich the inner space,   the first section includes the first opening, the gas diffusion path, and a section of the electrode inner surface on the side of the gas diffusion path, and   the second section includes a section of the electrode inner surface on the side opposite to the gas diffusion path.   
     
     
         14 . The discharge electrode according to  claim 1 , further comprising:
 a spacer disposed between the electrode inner surface and the pipe outer surface,   wherein the spacer is provided on the gas-pipe outer surface,   wherein a key is provided on the electrode inner surface, and   wherein a key groove that engages with the key is provided on the spacer.   
     
     
         15 . The discharge electrode according to  claim 1 ,
 wherein an eye mark indicating the position of the nozzle hole group is provided on the gas-pipe outer surface.   
     
     
         16 . A discharge electrode comprising:
 two lateral structures that are substantially parallel to each other and extend in a first direction; and   a plurality of longitudinal structures that are provided between the two lateral structures, are substantially parallel to each other, and extend in a second direction substantially orthogonal to the first direction,   wherein the plurality of longitudinal structures each include
 an electrode main body having one end connected to one of the lateral structures and the other end connected to the other lateral structure, the electrode main body extending in the second direction, 
 a gas block having one end connected to said one of the lateral structures and the other end connected to the other lateral structure, the gas block extending in the second direction, and 
 a porous body, 
   wherein the electrode main body includes a first opening open at a counter electrode holding a substrate; a first attachment section disposed on a side opposite to the first opening; a gas diffusion path provided between the first opening and the first attachment section and communicating with the first opening; and a second opening where the gas diffusion path opens at the first attachment section,   wherein the first opening, the first attachment section, the gas diffusion path, and the second opening extend in the second direction,   wherein the first opening is covered by the porous body,   wherein the gas block includes a gas flow path provided inside the gas block; a second attachment section; and a nozzle hole group which is provided between the gas flow path and the second attachment section to communicate with the gas flow path and opens at the section attachment section,   wherein the gas flow path and the second attachment section extend in the second direction,   wherein the nozzle hole group is arranged on the gas block in the second direction, and   wherein the gas block is attached to the electrode main body in a removable manner such that the first attachment section and the second attachment section engage and such that the nozzle hole group communicates with the gas diffusion path.   
     
     
         17 . A thin-film deposition apparatus comprising:
 a film deposition chamber;   a discharge electrode according to  claim 1 , disposed inside the film deposition chamber; and   a counter electrode opposing the discharge electrode and being disposed inside the film deposition chamber.   
     
     
         18 . A fabrication method of a solar cell using a thin-film deposition apparatus,
 wherein the thin-film deposition apparatus includes   a film deposition chamber;   a discharge electrode according to  claim 1 , disposed inside the film deposition chamber; and   a counter electrode opposing the discharge electrode and being disposed inside the film deposition chamber,   the method comprising the steps of:   (a) supporting a substrate by the counter electrode;   (b) introducing deposition gas to the film deposition chamber through the gas pipe, the nozzle hole group, the gas diffusion path, and the porous body; and   (c) depositing thin film for a solar cell by applying electrical power between the discharge electrode and the counter electrode while introducing the gas.   
     
     
         19 . A thin-film deposition apparatus comprising:
 a film deposition chamber;   a discharge electrode according to  claim 16 , disposed inside the film deposition chamber; and   a counter electrode opposing the discharge electrode and being disposed inside the film deposition chamber.   
     
     
         20 . A fabrication method of a solar cell using a thin-film deposition apparatus,
 wherein the thin-film deposition apparatus includes   a film deposition chamber;   a discharge electrode according to  claim 16 , disposed inside the film deposition chamber; and   a counter electrode opposing the discharge electrode and being disposed inside the film deposition chamber,   the method comprising the steps of:   (a) supporting a substrate by the counter electrode;   (b) introducing deposition gas to the film deposition chamber through the gas pipe, the nozzle hole group, the gas diffusion path, and the porous body; and   (c) depositing thin film for a solar cell by applying electrical power between the discharge electrode and the counter electrode while introducing the gas.